I very un-mathematically tried to get the perfect amount on my card so that it would come out to $0.00 when it was last swiped, but the best I could do without a paper, pen and/or calculator was down to $0.25 left on my card which isn’t bad. Problem is also that I have two Metrocards with cash on them right now so I’d love to get all the money out of one so I wouldn’t feel like I was wasting those small amounts when I threw the card away.

EDIT: My friend Fo just sent this link to me, thanks!Â http://www.nycmetrocardcalculator.com/

Hey, didn’t you have a tiger mom who taught you this math 🙂

The problem boils down to I*2.25=0,6+x*1.07 , where x is your top-up-amount and I is any integer number like 1, 2, 3, etc. The problem is finding a number I where x is a number that can be expressed in cents. The solution is that there is no EXACT number under 20 dollar which solves that equation 😛

Heh, I was actually very good in Math class before Calculus (I blame my terrible Calculus teacher) I just haven’t cared SO much to actually figure this out. Also, for amounts under $10 they don’t give additional money which is probably the real solution.